Radio frequency (RF) signals have delivered audio and video programming and similar information to distant locations for decades. As the demand for a mobile information society increases, the use of RF signals for data transfer has increased. Since RF signals are wireless, RF networks do not present a mobility challenge like hard-wired networks with connections such as land-based telephone lines or cable jacks. As the wireless transfer of information continues to increase in popularity, the high-speed wireless transmission of tremendous amounts of data is becoming more essential to the everyday function of many companies.
As a result, high-speed wireless data transfer has quickly become a highly profitable field of technology, with each competitor seeking the fastest data transfer capabilities, along with the fewest possible errors in the data stream. The traditional approach to wireless data transfer has been to employ RF signals to transmit the data from a transmitter to a distant receiver. With this conventional approach, data is first converted to an analog format so that it may be transmitted using RF signals. The data is then transmitted to a receiver by modulating the analog data on an RF carrier wave, amplifying the signal, and transmitting the signal to a waiting receiver. The receiver receiving the data signal demodulates the RF signal to extract the analog data stream, and forwards the data for conversion back to a binary format so that it may be used as desired.
A media access controller (MAC) in a transmitter and receiver is responsible for implementing the correct protocol for transmitting and receiving data via a designated media. The MAC typically includes some memory to store incoming and outgoing packets (buffers) and other data (configuration, statistics). The main characteristics of a typical MAC are the packet format (size, headers), the channel access mechanisms and the network management features. The amount of on-board memory may also be important, because the MAC may need a significant number of buffers to compensate for potential interface latencies.
A typical MAC protocol is the IEEE 802.11 standard. In 802.11, the MAC may use a contention resolution scheme that listens to a RF channel to determine if it is free. If so, then data may be sent via the RF channel. If the RF channel is not free, then the MAC will determine at another time if the channel is free. The contention resolution scheme, therefore, may be time costly which may translate to a reduced data bit rate.
Accordingly, what is needed in the art is a method for accessing a media and a media access controller which avoids delay by using multiple frequencies and time slots in parallel.